Laws of Shell-Growth in English Native Oysters (Ostrea edulis)

Abstract

ON investigating recently an economic problem on growth in the native oyster, Ostrea edulis, close relations were found between volume and weight of the entire animal, and both mean diameter and mean axis of the shell (mean axis being the mean of the described¹ dimensions of length, breadth—or height zoologically, and width—or thickness). As oysters are measured in wooden tubs (4 wash = one tub) on the oyster-beds and mean diameter is the simplest criterion of size, volume and mean diameter are the most interesting relations economically. Volumes and mean diameters for Essex native oysters from Roach River are given in Fig. 1, R¹, and show a close approximation to the relation y = 0.0404 x^3.531 where y is volume in c.c. and x = mean diameter in cm. The plottings are of samples of 10–40 oysters estimated at 2, 2 or 3, 3, 4, 4 or 5, and 5 years of age, with additional samples of small oysters, for which I am greatly indebted to Mr. Austin Gardner and M. Rigoine de Fougerolles. Samples of tiny oysters grown in 1934 in the sea were obtained living on a limed tile from France and are plotted, since English spat attached to shell are difficult to detach whole, and any difference between English and French spat is estimated to be non-significant on the scale shown.